IERS Earth Orientation Parameter data: provider permission and attribution

This notice concerns the EOP (IERS) 20 C04 numeric data snapshot distributed
with GMAT Py as data/planetary_coeff/eopc04_08.62-now. The legacy filename is
retained for compatibility; the actual header identifies IERS 20 C04 in an
old-format layout, with offsets compatible with the IAU 1980 model. This is
not an assertion that IERS data are under Apache-2.0, CC BY, or public domain.

Provider: IERS Earth Orientation Parameter Product Centre, Observatoire de
Paris / SYRTE. Retain this attribution and the data-reference links:
  https://hpiers.obspm.fr/eop-pc/index.php?index=C04&lang=en
  https://hpiers.obspm.fr/iers/eop/eopc04/readme
  https://hpiers.obspm.fr/iers/eop/eopc04/

Christian Bizouard of the IERS EOP Centre confirmed the following on
9 April 2017, in a reply publicly forwarded by Marshall Eubanks:

"I confirm that IERS allows for unlimited copying and use of this and other
EOP file,...as far you mention the reference!"

Archived source of that provider statement:
  https://lists.iana.org/hyperkitty/list/tz%40iana.org/message/DSTTJE5RC3PSYHPBVNR7J3FFDZMFH4TW/
  https://lists.iana.org/hyperkitty/list/tz%40iana.org/message/DSTTJE5RC3PSYHPBVNR7J3FFDZMFH4TW/attachment/2/attachment.html

The statement covers this family of EOP files generally. The retained file
names the same provider contact. The project records this permission with
attribution as its redistribution basis, preserving the provider header and
numeric snapshot. It does not assert an unrelated open-license designation.

Scientific snapshot limits: this file ends on 2026-09-14. Later rows carry
forecast/error sentinel fields (including 0.999); those must not be mistaken
for current final observations. The package does not download updates.
Consult the manifest for exact file identity and date-range evidence.

No assurance of numerical accuracy, suitability, or legal outcome is made.
